The single-occupant vehicle has thrived since the end of World War II and the need for an abundance of convenient parking has mirrored this growth. Currently, there are an estimated 1 billion to 2 billion parking spaces — surface, garageandstreetparking—inthe U.S., coveringbetween

16,000 and 25,000 square miles of land. That is comparable to the geographic area of
Massachusetts and New Jersey combined. This means there are between four and eight
parking spaces for every registered passenger vehicle in this country.

In suburban areas, parking is usually plentiful and free as a function of lower land
values. In dense urban cities, surface and garage parking facilities only make sense
when they are profitable, which is a function of user costs, operating costs and
demand. As the prevalence of automation technology for transportation grows, the
use of surface and structured parking spaces in urban areas is expected to decline,
since fully autonomous vehicles will be able to work without drivers. Factors such as
mass-transit developments and telecommuting trends also are likely to contribute to a
decline in the demand for parking spaces.

Degrees of automation

Autonomous vehicles (AVs), or self-driving cars, have been talked about for years and
are frequently mentioned in science fiction, but government and private-industry officials should start planning for their arrival in the real world. AV is a reference to vehicles
that may have both autonomous and connected-vehicle technology. There are many
potential benefits to AV technology, including improved safety, increased roadway
capacity and improved parking efficiency.

There are different degrees of automation, ranging from Level 0, which requires a human driver at all times, to Level 5, which allows fully autonomous operation with all road
types, speeds and environmental conditions. Level 4 and 5 vehicles can drive themselves
and operate on most roadways without a driver present in the vehicle. These degrees of
automation will have the most direct impact upon travel behavior and, indirectly, upon
land use.

With the average lifespan of a passenger vehicle in the U.S. reaching 11. 5 years, it
will take time for AV technology to spread. Researchers estimate that by 2040, up to 60

percent of all passenger vehicles sold in the U.S. will be at Level 4 automation and up to

50 percent of roadway travel will be done using AVs. The technology may not only influence single-occupancy vehicles, given ride-sharing and ride-sourcing services like Uber
and Lyft have a small but increasing share of vehicle trips in major urban areas. Public
transportation and the freight industry also may undergo transformations.

Parking garages

Off-street parking can be expensive in an urban setting with high land values. Construction costs can easily exceed $20,000 per space for underground parking in urban areas,
not counting land-acquisition costs. Annual operation and maintenance costs can run
from $100 to $500 per space. And the annual user costs for garage parking in a city like
Boston can be $4,500 or more.

It is expensive to build, support and pay for parking structures in urban downtown
cores. In addition to the direct costs of building and maintaining the facilities, parking
takes up space that could otherwise be used for additional commercial or residential
purposes. It also results in environmental costs, including increased stormwater runoff,
air pollution and “heat islands,” urban areas that are warmer than their surroundings
due to human activity.

The location of a parking structure depends on the number of spaces needed and
on the value of land where the facility is found. If the need for urban parking spaces
shrinks because of automated-vehicle technology, property developers and operators
will need to rethink the profit margins for building and maintaining these facilities.